1. Field of the Invention
The invention relates in general to methods for propagating object attribute values among objects in a data processing system, and in particular to methods for enhancing access and options for changing object attribute values among groups of objects. Still more particularly, the invention relates to methods for defining propagation groups for object attribute values without limitation of object rank or predefined object relationships.
2. Description of the Prior Art
In data processing, the term "object" refers to a collection of data referred to by a single name. An object is identified both to the computer and to a user by its name. An object has "attributes" which relate to manipulation of the object by the computer. At the most basic level, a name is an attribute of all objects. A specific name for an object is an attribute value. An example of an object is a word processing document. Those skilled in the art will appreciate that a word processing document will have a name, a font, a line spacing definition, and a background color. These are attributes. Their specific manifestation are object attribute values.
Objects of an "object type" are related by attributes that define the purpose of the objects within a data processing system. Each object type has associated with it a set of commands with which to process that type. Membership in an "object class" is more arbitrary. A class is a category to which objects are assigned or defined.
The categorization of object as being of object types or object classes is not merely a semantic exercise, but underlies the basic organization of data within a computer Object types and classes exist in a particular object hierarchy within the data processing system. System level and program level objects are at the top of the hierarchy. User oriented objects such as word processing documents exist at intermediate or lower levels of the hierarchy. Thus an object may depend upon another object in a chain linking level to level.
The prior art teaches propagation of attribute values downward in such chains. Returning to the example of word processing texts, the opening of a word processing text file automatically embraces certain default attribute values established by the parent object, here the word processing program. This is the conventional approach for dealing with object attribute values, which allows for inheritance of those properties by subobjects of an object. This scheme of object values propagation is limited to one way inheritance, downwards in an object hierarchy. The scheme does not permit propagation of attribute values within a level among objects of the same object type. Nor does the prior scheme permit propagation of attribute values among arbitrarily co-categorized objects.
Thus, it is one object of the present invention to provide a method of enhancing propagation of object attribute values among objects in a data processing system.
It is another object of the present invention to provide a method for enhancing access to attribute values for an object type on a particular level in a data hierarchy.
It is yet another object of the invention to provide a method for defining propagation groups for particular object attribute values without limitation of object rank or predefined interrelationships among objects.